Error when I value the pitchband in the midnote

I have an error that I haven’t solved for a long time.
I activated ‘Key Editor’ in the Cubase10 and created a MidiNote.
But, When I drag the point on the pitchband at the bottom of the screen and double-click to set the value at the top of the screen, ‘value’ automatically drops to the lowest setting (-8192) .